Display panel

ABSTRACT

A display panel includes a substrate, a plurality of pixels, a plurality of scan lines, a pull-down control circuit, and a gate driving circuit. The pixels are disposed on a display area of the substrate. The scan lines are disposed on the substrate and respectively coupled to the corresponding pixels. The pull-down control circuit is disposed on a peripheral area of the substrate, receives a plurality of clock signals, and has a plurality of pull-down units to provide a plurality of pull-down signals. The gate driving circuit is disposed on the peripheral area and has a plurality of shift registers. The shift registers are coupled to the scan lines to provide a plurality of gate driving signals and pull down the gate driving signals in sequence according to the pull-down signals. The pull-down control circuit and the gate driving circuit are arranged along a side of the display area.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan applicationserial no. 102115086, filed on Apr. 26, 2013. The entirety of theabove-mentioned patent application is hereby incorporated by referenceherein and made a part of this specification.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to a display panel, and especially, to a displaypanel having a multi-split type (MST) circuit architecture.

2. Description of Related Art

In recent years, as semiconductor technology flourishes, portableelectronic products and flat display products have been developedaccordingly. Due to the driving modes and the display effects, activedisplay panels have been commonly used. In general, pixels in the activedisplay panel are turned on through gate driving signals provided bygate driving chips, so as to set the brightness (or gray-level values)displayed by the pixels. In order to reduce production costs of liquidcrystal displays, some of the manufacturers have brought forward theapplication of thin film transistors (TFT) directly on glass substratesto make multi-stage shift registers, thereby replacing theconventionally used gate driving chips to reduce production costs offlat displays.

In flat displays, the circuit area of the shift registers disposed inthe display panel affects the circuit area of the pixels disposed in thedisplay panel, which relatively affects the overall size and appearanceof the flat displays. Therefore, relevant display industries havealready invested in slim border design in order to make slim and compactdisplays without sacrificing the display quality, so as to satisfyconsumers' requirements.

SUMMARY OF THE INVENTION

The invention provides a display panel which removes control units froma gate driving circuit to reduce a circuit area of the gate drivingcircuit and to further slim down a border of the display panel.

The invention provides a display panel which includes a substrate, aplurality of pixels, a plurality of scan lines, a pull-down controlcircuit, and a gate driving circuit. The substrate has a display areaand a peripheral area. The pixels are disposed on the display area. Thescan lines are disposed on the substrate, are respectively coupled tothe corresponding pixels, and extend from the display area to theperipheral area. The pull-down control circuit is disposed on theperipheral area, receives a plurality of clock signals, and has aplurality of pull-down units to provide a plurality of first pull-downsignals. The gate driving circuit is disposed on the peripheral area andhas a plurality of shift registers. The shift registers are coupled tothe scan lines to provide a plurality of gate driving signals, and theshift registers are coupled to the pull-down control circuit to receivethe first pull-down signals. The shift registers enable the gate drivingsignals in sequence according to the clock signals and pull down thegate driving signals in sequence according to the first pull-downsignals, respectively. The pull-down control circuit and the gatedriving circuit are arranged along a side of the display area.

In light of the above, in the embodiments of the invention, the displaypanel removes the pull-down control units from the shift registers ofthe gate driving circuit, so that the removed pull-down control unitsbecome an independent pull-down control circuit. Furthermore, in theembodiments of the invention, the gate driving circuit and the pull-downcontrol circuit of the display panel are arranged in sequence along aside of the display area to reduce the circuit area of the gate drivingcircuit and to slim down the border of the display panel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic system diagram of a display panel according to anembodiment of the invention.

FIG. 2A is a schematic circuit diagram of a shift register according toan embodiment of the invention.

FIG. 2B is a schematic circuit diagram of a pull-down unit according toan embodiment of the invention.

FIG. 2C is a schematic waveform diagram of clock signals and gatedriving signals according to an embodiment of the invention.

FIG. 3A is a schematic circuit diagram of a shift register according toanother embodiment of the invention.

FIG. 3B is a schematic circuit diagram of a pull-down unit according toanother embodiment of the invention.

FIG. 4 is a schematic system diagram of a display panel according toanother embodiment of the invention.

FIG. 5A is a schematic circuit diagram of a shift register according tostill another embodiment of the invention.

FIG. 5B is a schematic circuit diagram of a pull-down unit according tostill another embodiment of the invention.

FIG. 5C is a schematic circuit diagram of a pull-down unit according toyet another embodiment of the invention.

FIG. 6 is a schematic system diagram of a display panel according tostill another embodiment of the invention.

FIG. 7A is a schematic circuit diagram of a shift register according toyet another embodiment of the invention.

FIG. 7B is a schematic circuit diagram of a push-up unit according to anembodiment of the invention.

FIG. 8 is a schematic system diagram of a display panel according to yetanother embodiment of the invention.

DESCRIPTION OF EMBODIMENTS

FIG. 1 is a schematic system diagram of a display panel according to anembodiment of the invention. The display panel 100 includes a substrate110, a plurality of pixels PX, a plurality of scan lines 115, gatedriving circuits 120_1 and 120_2, and pull-down control circuits 130_1and 130_2. The substrate 100 has a display area 111 and a peripheralarea 113. The pixels PX are disposed on the display area 111. The scanlines 115 are disposed on the substrate 111, are respectively coupled tothe corresponding pixels PX, and extend from the display area 111 to theperipheral area 113, so that the scan lines 115 are coupled to thecorresponding gate driving circuits (such as 120_1 and 120_2).

The pull-down control circuit 130_1 is disposed on the peripheral area113, receives a plurality of clock signals (e.g., four clock signalsCK1L, CK1BL, CK2L, and CK2BL), and has a plurality of pull-down units131 to provide a plurality of the first pull-down signals (such as D11to D13). Similarly, the pull-down control circuit 130_2 is also disposedon the peripheral area 113 and receives a plurality of clock signals(e.g., four clock signals CK1R, CK1BR, CK2R, and CK2BR) to provide aplurality of first pull-down signals (such as D21 to D23), whereinoperation of the pull-down control circuit 130_2 may refer to that ofthe pull-down control circuit 130_1. Herein, phases of the clock signalsCK1L, CK1BL, CK2L, and CK2BL, which are received by the pull-downcontrol circuit 130_1, can respectively lead those of the clock signalsCK1R, CK1BR, CK2R, and CK2BR, which are received by the pull-downcontrol circuit 130_2.

The gate driving circuit 120_1 is disposed on the peripheral area 113and has a plurality of shift registers 121. The shift registers 121 arecoupled to one of the scan lines 115 respectively to provide a pluralityof odd-numbered gate driving signals (such as G1 and G3) to the scanlines 115. Moreover, the shift registers 121 are coupled to thepull-down control circuit 130_1 to receive the corresponding firstpull-down signals (such as D11 to D13). The shift registers 121 enablethe odd-numbered gate driving signals (such as G1 and G3) in sequenceaccording to the clock signals CK1L, CK1BL, CK2L, and CK2BL and pulldown the odd-numbered gate driving signals (such as G1 and G3) insequence according to the first pull-down signals (such as D11 to D13)respectively, wherein the pull-down control circuit 130_1 and the gatedriving circuit 120_1 are arranged in sequence along a left side of thedisplay area 111.

The gate driving circuit 120_2 is disposed on the peripheral area 113,wherein the gate driving circuit 120_2 is coupled to the scan lines 115to provide a plurality of even-numbered gate driving signals (such as G2and G4) to the scan lines 115 and is coupled to the pull-down controlcircuit 1302 to receive the corresponding first pull-down signals (suchas D21 to D23). The gate driving circuit 120_2 enables the even-numberedgate driving signals (such as G2 and G4) in sequence according to theclock signals CK1R, CK1BR, CK2R, and CK2BR and pull down theeven-numbered gate driving signals (such as G2 and G4) in sequenceaccording to the first pull-down signals (such as D21 to D23)respectively, wherein operation of the gate driving circuit 120_2 mayrefer to that of the gate driving circuit 120_1, and the pull-downcontrol circuit 130_2 and the gate driving circuit 120_2 are arranged insequence along a right side of the display area 111.

According to the above, since the gate driving circuits 120_1 and 120_2pull down the gate driving signals (such as G1 to G4) according to thefirst pull-down signals (such as D11 to D13 and D21 to D23), circuits ofthe shift registers 121 used to decide the pull-down time sequence ofthe gate driving signals (such as G1 to G4) may be removed withoutaffecting operation of the shift registers 121. Thereby, the circuitarea of the gate driving circuits 120_1 and 120_2 may be reduced, so asto slim down a border of the display panel.

Additionally, in the present embodiment, the pull-down control circuit130_1 is disposed below the gate driving circuit 120_1. In otherembodiments, however, the pull-down control circuit 130_1 may bedisposed above the gate driving circuit 120_1 or the pull-down controlcircuit 130_1 may be disposed both sides of below and above the gatedriving circuit 120_1 at the same time, which may be modified by thosehaving ordinary skill in the art. Similarly, the pull-down controlcircuit 130_2 may not only be disposed below the gate driving circuit120_2 but also be disposed above the gate driving circuit 120_2 or thepull-down control circuit 130_2 may be disposed both sides of below andabove the gate driving circuit 120_2 at the same time.

FIG. 2A is a schematic circuit diagram of a shift register according toan embodiment of the invention. Please refer to FIG. 1 and FIG. 2A. Inthe present embodiment, the shift register 121 a is an example of theshift register 121 in the gate driving circuit 120_1, and the exemplaryshift register 121 outputs the gate driving signal G3 (corresponding tothe i^(th) gate driving signal, wherein i is an positive integer). Inaddition, the shift register 121 a is assumed to be capable ofperforming bidirectional scanning and receiving the first pull-downsignal D12. In the present embodiment, the shift register 121 a includesa pre-charge unit 210, a voltage push-up unit 220, and a voltagepull-down unit 230. The pre-charge unit 210 includes transistors T1 andT2 (corresponding to the first transistor and the second transistor).The voltage push-up unit 220 includes a transistor T5 (corresponding tothe fifth transistor) and a capacitor C1 (corresponding to the firstcapacitor). The voltage pull-down unit 230 includes transistors T3 andT4 (corresponding to the third transistor and the fourth transistor).

A source of the transistor T1 (corresponding to the first terminal)receives a forward scanning voltage VF, a drain of the transistor T1(corresponding to the second terminal) is coupled to an internal voltageQ, and a gate of the transistor T1 (corresponding to the controlterminal) receives the gate driving signal G1 (corresponding to the(i−1)^(th) gate driving signal). A source of the transistor T2(corresponding to the first terminal) receives a reverse scanningvoltage VB, a drain of the transistor T2 (corresponding to the secondterminal) is coupled to the internal voltage Q, and a gate of thetransistor T2 (corresponding to the control terminal) receives the gatedriving signal G5 (corresponding to the (i+1)^(th) gate driving signal).The forward scanning voltage VF is one of a gate high voltage (such as15 volts) and a gate low voltage VGL (such as −10 volts), and thereverse scanning voltage VB is the other one of the gate high voltageand the gate low voltage. In other words, when the display panel 100performs forward scanning, the forward scanning voltage VF is the gatehigh voltage, and the reverse scanning voltage VB is the gate lowvoltage; when the display panel 100 performs reverse scanning, theforward scanning voltage VF is the gate low voltage, and the reversescanning voltage VB is the gate high voltage.

According to the above, when the display panel 100 performs forwardscanning, and the gate driving signal G1 is enabled, the enabled gatedriving signal G1 charges the internal voltage Q through the turned-ontransistor T1; when the display panel 100 performs reverse scanning, andthe gate driving signal G5 is enabled, the enabled gate driving signalG5 charges the internal voltage Q through the turned-on transistor T2.Therefore, the pre-charge unit 210 can pre-charge the internal voltageQ.

A drain of the transistor T5 (corresponding to the first terminal)receives the clock signal CK2L (corresponding to the first clocksignal), a source of the transistor T5 (corresponding to the secondterminal) is coupled to the gate driving signal G3, and a gate of thetransistor T5 (corresponding to the control terminal) receives theinternal voltage Q. The capacitor C1 is coupled between the source andthe drain of the transistor T5. Therefore, the voltage push-up unit 220can push up the gate driving signal G3 according to the internal voltageQ.

A drain of the transistor T3 (corresponding to the first terminal)receives the internal voltage Q, a source of the transistor T3(corresponding to the second terminal) receives the gate low voltageVGL, and a gate of the transistor T3 (corresponding to the controlterminal) receives the corresponding first pull-down signal D12.Therefore, the voltage pull-down unit 230 can pull down the internalvoltage Q and the gate driving signal G3 according to the firstpull-down signal D12.

FIG. 2B is a schematic circuit diagram of a pull-down unit according toan embodiment of the invention. Please refer to FIG. 1 and FIG. 2B. Inthe present embodiment, the pull-down unit 131 a includes transistors T6and T7 (corresponding to the sixth transistor and the seventhtransistor). A drain of the transistor T6 (corresponding to the firstterminal) receives the forward scanning voltage VF, a source of thetransistor T6 (corresponding to the second terminal) is coupled to thefirst pull-down signal D12, and a gate of the transistor T6(corresponding to the control terminal) receives the clock signal CK1BL(corresponding to the second clock signal). A drain of the transistor T7(corresponding to the first terminal) receives the reverse scanningvoltage VB, a source of the transistor T7 (corresponding to the secondterminal) is coupled to the first pull-down signal D12, and a gate ofthe transistor T7 (corresponding to the control terminal) receives theclock signal CK1L (corresponding to the third clock signal). The forwardscanning voltage VF and the reverse scanning voltage VB may be set inthe same manner as described in the embodiment shown in FIG. 2A and isthus not reiterated herein.

FIG. 2C is a schematic waveform diagram of clock signals and gatedriving signals according to an embodiment of the invention. Pleaserefer to FIG. 1, FIG. 2A, FIG. 2B, and FIG. 2C. In the presentembodiment, enabling periods of the clock signals CK1L, CK1BL, CK2L andCK2BL partially overlap with one another and are not exactly the same,wherein the clock signal CK1BL can be regarded as an inverse signal ofthe clock signal CK1L (that is, having 180-degree phase difference), andthe clock signal CK2BL can be regarded as an inverse signal of the clocksignals CK2L (that is, having 180-degree phase difference). Herein, thedisplay panel 100 performing forward scanning is exemplified forillustration, and the display panel 100 performing reverse scanning canthen be understood accordingly.

When the gate driving signal G1 is enabled, the forward scanning voltageVF, which is the gate high voltage, pre-charges the internal voltage Q.When the clock signal CK2L is enabled, the voltage level of the gatedriving signal G2 is pushed up (which is regarded as enabling). When theclock signal CK1BL is enabled, the voltage level of the first pull-downsignal D12 is pushed up (which is regarded as enabling), so that thevoltage level of the internal voltage Q and the voltage level of thegate driving signal G3 are pulled down to the gate low voltage VGL.According to the above, the enabling period of the clock signal CK2L andthe enabling period of the clock signal CK1BL partially overlap, and theenabling period of the clock signal CK2L and the enabling period of theclock signal CK1L partially overlap. Moreover, a phase of the clocksignal CK2L leads that of the clock signal CK1BL, and the phase of theclock signal CK2L lags that of the clock signal CK1L.

As shown in FIG. 2A, when the shift register 121 a is assumed to outputthe gate driving signal G1, the gate of the transistor T1 can be coupledto a start signal STVL, so that the pre-charge unit 210 of the shiftregister 121 a, which outputs the gate driving signal G1, can pre-chargethe internal voltage.

FIG. 3A is a schematic circuit diagram of another shift registeraccording to another embodiment of the invention. Please refer to FIG.1, FIG. 2A, and FIG. 3A. In the present embodiment, the shift register121 b is substantially the same as the shift register 121 a. The shiftregister 121 b is assumed to perform unidirectional scanning, whereinthe same or similar reference numbers as those in the first embodimentare used herein to represent the same or similar components. Thedifference between the shift registers 121 a and 121 b lies in apre-charge unit 310 of the shift register 121 b. Specifically, thepre-charge unit 310 includes a transistor T8 (corresponding to the ninthtransistor). A source (corresponding to the first terminal) and a gate(corresponding to the control terminal) of the transistor T8 receive thegate driving signal G1, and a drain (corresponding to the second tenfinal) of the transistor T8 is coupled to the internal voltage Q.

FIG. 3B is a schematic circuit diagram of a pull-down unit according toanother embodiment of the invention. Please refer to FIG. 1 and FIG. 3B.In the present embodiment, a pull-down unit 131 b includes a transistorT9 (corresponding to the eighth transistor). A drain (corresponding tothe first terminal) and a gate (corresponding to the control terminal)of the transistor T9 receive the clock signal CK1BL (corresponding tothe fourth clock signal), and a source of the transistor T9(corresponding to the second terminal) is coupled to the first pull-downsignal D12. As shown in FIG. 2C, the enabling period of the clock signalCK2L and the enabling period of the clock signal CK1BL partiallyoverlap, and the phase of the clock signal CK2L leads that of the clocksignal CK1BL.

FIG. 4 is a schematic system diagram of a display panel according toanother embodiment of the invention. Please refer to FIG. 1 and FIG. 4.The display panel 400 is substantially the same as the display panel100. The differences between the display panels 400 and 100 lie in gatedriving circuits 420_1 and 420_2 and pull-down control circuits 430_1and 430_2, wherein the same or similar reference numbers are used hereinto represent the same or similar components. The pull-down controlcircuit 430_1 has a plurality of pull-down units 431 to provide aplurality of the first pull-down signals (such as D11 to D13) and aplurality of the second pull-down signals (such as D31 to D33) to thegate driving circuit 420_1. The pull-down control circuit 430_2 providesa plurality of the first pull-down signals (such as D21 to D23) and aplurality of the second pull-down signals (such as D41 to D43) to thegate driving circuit 4202, wherein operation of the pull-down controlcircuit 430_2 may refer to that of the pull-down control circuit 430_1.

The gate driving circuit 420_1 has a plurality of shift registers 421 toprovide a plurality of odd-numbered gate driving signals (such as G1 andG3), and each shift register 421 pulls down the correspondingodd-numbered gate driving signal (such as G1 and G3) and its internalvoltage Q according to the corresponding first pull-down signal (such asD11 to D13) and the corresponding second pull-down signal (such as D31to D33). The gate driving circuit 420_2 serves to provide a plurality ofeven-numbered gate driving signals (such as G2 and G4), and operation ofthe gate driving circuit 420_2 may refer to that of the gate drivingcircuit 420_1.

FIG. 5A is a schematic circuit diagram of a shift register according tostill another embodiment of the invention. Please refer to FIG. 2A, FIG.4, and FIG. 5A. The shift register 421 a is substantially the same asthe shift register 121 a, and the difference lies in a voltage pull-downunit 530, wherein the same or similar reference numbers are used hereinto represent the same or similar components. In the present embodiment,the shift register 421 a is assumed to receive the first pull-downsignal D12 and the second pull-down signal D32, and the shift register421 a outputs the gate driving signal G3. The voltage pull-down unit 530includes transistors T10 to T12 (corresponding to the tenth transistorto the twelfth transistor).

A drain of the transistor T10 (corresponding to the first terminal)receives the second pull-down signal D32, a source of the transistor T10(corresponding to the second terminal) receives the gate low voltageVGL, and a gate of the transistor T10 (corresponding to the controlterminal) receives the internal voltage Q. A drain of the transistor T11(corresponding to the first terminal) is coupled to the internal voltageQ, a source of the transistor T11 (corresponding to the second terminal)receives the gate low voltage VGL, and a gate of the transistor T11(corresponding to control terminal) receives the second pull-down signalD32. A drain of the transistor T12 (corresponding to the first terminal)is coupled to the gate driving signal G3, a source of the transistor T12(corresponding to the second terminal) receives the gate low voltageVGL, and a gate of the transistor T12 (corresponding to the controlterminal) receives the first pull-down signal D12.

FIG. 5B is a schematic circuit diagram of a pull-down unit according tostill another embodiment of the invention. Please refer to FIG. 4 andFIG. 5B. In the present embodiment, a pull-down unit 431 a includestransistors T13 to T16 (corresponding to the thirteenth transistor tothe sixteenth transistor). A drain of the transistor T13 (correspondingto the first terminal) receives the forward scanning voltage VF, asource of the transistor T13 (corresponding to the second terminal) iscoupled to the first pull-down signal D12, and a gate of the transistorT13 (corresponding to the control terminal) receives the clock signalCK1BL (corresponding to the fifth clock signal). A drain of thetransistor T14 (corresponding to the first terminal) receives thereverse scanning voltage VB, a source of the transistor T14(corresponding to the second terminal) is coupled to the first pull-downsignal D12, and a gate of the transistor T14 (corresponding to thecontrol terminal) receives the clock signal CK1L (corresponding to thesixth clock signal).

A drain of the transistor T15 (corresponding to the first terminal)receives the forward scanning voltage VF, a source of the transistor T15(corresponding to the second terminal) is coupled to the secondpull-down signal D32, and a gate of the transistor T15 (corresponding tothe control terminal) receives the clock signal CK2L (corresponding tothe fifth clock signal). A drain of the transistor T16 (corresponding tothe first terminal) receives the reverse scanning voltage VB, a sourceof the transistor T16 (corresponding to the second terminal) is coupledto the second pull-down signal D32, and a gate of the transistor T16(corresponding to the control terminal) receives the clock signal CK2BL(corresponding to the sixth clock signal). The forward scanning voltageVF and the reverse scanning voltage VB may be set in the same manner asdescribed in the embodiment shown in FIG. 2A and is not reiteratedherein.

FIG. 5C is a schematic circuit diagram of a pull-down unit according toyet another embodiment of the invention. Please refer to FIG. 5A to FIG.5C. In the embodiment shown in FIG. 5A and FIG. 5B, the shift registersare applied to bidirectional scanning, whereas the pull-down unit 431 bdescribed herein is the shift register which is applied tounidirectional scanning. For instance, the pre-charge unit 210 of theshift register 421 a is replaced by the pre-charge unit 310 shown inFIG. 3A. The pull-down unit 431 b includes transistors T17 and T18(corresponding to the seventeenth transistor and the eighteenthtransistor). A drain (corresponding to the first terminal) and a gate(corresponding to the control terminal) of the transistor T17 receivethe clock signal CK1BL (corresponding to the fifth clock signal), and asource of the transistor T17 (corresponding to the second terminal) iscoupled to the first pull-down signal D12. A drain (corresponding to thefirst terminal) and a gate (corresponding to the control terminal) ofthe transistor T18 receive the clock signal CK2L (corresponding to thefifth clock signal), and a source of the transistor T18 (correspondingto the second terminal) is coupled to the second pull-down signal D32.As shown in FIG. 2C, enabling periods of the clock signals CK1BL andCK2L partially overlap, and the phase of the clock signal CK2L leadsthat of the clock signal CK1BL.

FIG. 6 is a schematic system diagram of a display panel according tostill another embodiment of the invention. Please refer to FIG. 1 andFIG. 6. A display panel 600 is substantially the same as the displaypanel 100. The differences between the display panels 600 and 100 lie ingate driving circuits 620_1 and 620_2 and push-up control circuits 630_1and 630_2, wherein the push-up control circuits 630_1 and 630_2 aredisposed on the peripheral area 113. The same or similar referencenumbers are used herein to represent the same or similar components. Thepush-up control circuit 630_1 receives the clock signals CK1L, CK1BL,CK2L, and CK2BL, and the push-up control circuit 630_2 receives theclock signals CK1R, CK1BR, CK2R, and CK2BR. The push-up control circuit630_1 has a plurality of push-up units 631 to provide a plurality ofpush-up signals (such as U11 to U13) to the gate driving circuit 620_1according to the clock signals CK1L, CK1BL, CK2L, and CK2BL. The push-upcontrol circuit 630_2 provides a plurality of push-up signals (such asU21 to U23) to the gate driving circuit 620_2 according to the clocksignals CK1R, CK1BR, CK2R, and CK2BR, wherein operation of the push-upcontrol circuit 630_2 may refer to that of the pull-down control circuit630_1.

The gate driving circuit 620_1 has a plurality of shift registers 621 toprovide a plurality of odd-numbered gate driving signals (such as G1 andG3), wherein each shift register 621 pulls down the correspondingodd-numbered gate driving signal (such as G1 and G3) according to thecorresponding first pull-down signal (such as D11 to D13) and pushes upthe corresponding odd-numbered gate driving signal (such as G1 and G3)according to the corresponding push-up signal (such as U11 to U13). Thatis, each shift register 621 enables the corresponding odd-numbered gatedriving signal (such as G1 and G3). The gate driving circuit 620_2 is toprovide a plurality of even-numbered gate driving signals (such as G2and G4), wherein operation of the gate driving circuit 620_2 may referto that of the gate driving circuit 620_1.

The gate driving circuit 620_1 and the push-up control circuit 630_1 arearranged in sequence along a left side of the display area 111; the gatedriving circuit 620_2 and the push-up control circuit 630_2 are arrangedin sequence along a right side of the display area 111. In the presentembodiment, the push-up control circuit 630_1 is disposed below the gatedriving circuit 620_1. In other embodiments, however, the push-upcontrol circuit 630_1 may be disposed above the gate driving circuit620_1 or the push-up control circuit 630_1 may be disposed both sides ofbelow and above the gate driving circuit 620_1 at the same time, whichmay be modified by people having ordinary skill in the art. Similarly,the push-up control circuit 630_2 may not only be disposed below thegate driving circuit 620_2 but also be disposed above the gate drivingcircuit 620_2 or the push-up control circuit 630_2 may be disposed bothsides of below and above the gate driving circuit 620_2 at the sametime.

FIG. 7A is a schematic circuit diagram of a shift register according toyet another embodiment of the invention. Please refer to FIG. 2A, FIG.6, and FIG. 7A. The shift register 621 a is substantially the same asthe shift register 121 a, and the difference lies in a voltage push-upunit 720, wherein the same or similar reference numbers are used hereinto represent the same or similar components. In the present embodiment,the shift register 621 a is assumed to receive the first pull-downsignal D12 and the push-up signal U12, and the shift register 621 aoutputs the gate driving signal G3. The voltage push-up unit 720includes transistors T19 and T20 (corresponding to the nineteenthtransistor and the twentieth transistor).

A drain of the transistor T19 (corresponding to the first terminal)receives the push-up signal U12, and a gate of the transistor T19(corresponding to the control terminal) receives the internal voltage Q.A source of the transistor T20 (corresponding to the first terminal) iscoupled to the gate high voltage VGH, a drain of the transistor T20(corresponding to the second terminal) is coupled to the gate drivingsignals G3, and a gate of the transistor T20 (corresponding to controlterminal) is coupled to a source of the transistor T19 (corresponding tothe second terminal).

FIG. 7B is a schematic circuit diagram of a push-up unit according to anembodiment of the invention. Please refer to FIG. 6 and FIG. 7B. In thepresent embodiment, a push-up unit 631 a includes transistors T21 andT22 (corresponding to the twenty-first transistor and the twenty-secondtransistor) and a capacitor C2 (corresponding to the second capacitor).A drain (corresponding to the first terminal) and a gate (correspondingto the control terminal) of the transistor T21 receive the clock signalCK1L (corresponding to the eleventh clock signal), and a source of thetransistor T21 (corresponding to the second terminal) is coupled to thepush-up signal U12. A drain (corresponding to the first terminal) and agate (corresponding to the control terminal) of the transistor T22receive the clock signal CK2L (corresponding to the twelfth clocksignal). The capacitor C2 is coupled between a source of the transistorT22 (corresponding to the second terminal) and the push-up signal U12.As shown in FIG. 2C, enabling periods of the clock signals CK1L and CK2Lpartially overlap, and the phase of the clock signal CK1L leads that ofthe clock signal CK2L.

FIG. 8 is a schematic system diagram of a display panel according to yetanother embodiment of the invention. Please refer to FIG. 4, FIG. 6, andFIG. 8. A display panel 800 is substantially the same as the displaypanel 600, but the pull-down control circuits 130_1 and 130_2 of thedisplay panel 600 are replaced by pull-down control circuits 430_1 and430_2 as shown in FIG. 4. Furthermore, the main difference lies in gatedriving circuits 820_1 and 820_2, wherein the same or similar referencenumbers are used herein to represent the same or similar components.

The gate driving circuit 820_1 has a plurality of shift registers 821 toprovide a plurality of odd-numbered gate driving signals (such as G1 andG3), wherein each shift register 821 pulls down the correspondingodd-numbered gate driving signal (such as G1 and G3) and its internalvoltage Q according to the corresponding first pull-down signal (such asD11 to D13) and the corresponding second pull-down signal (such as D31to D33), and each shift registers 821 pushes up the correspondingodd-numbered gate driving signal (such as G1 and G3) according to thecorresponding push-up signal (such as U11 to U13). That is, each shiftregister 821 enables the corresponding odd-numbered gate driving signal(such as G1 and G3). The gate driving circuit 8202 is to provide aplurality of even-numbered gate driving signals (such as G2 and G4), andoperation of the gate driving circuit 820_2 may refer to that of thegate driving circuit 820_1.

When the shift register 821 is the shift register performingbidirectional scanning, the circuit of the shift register 821 may referto those shown in FIG. 5A and FIG. 7A. That is, the circuit of the shiftregister 821 is similar to the circuit of the shift register 621 a butthe voltage pull-down unit 230 thereof is replaced with the pull-downunit 530 of the shift register 421 a. Alternatively, when the shiftregister 821 is the shift register performing unidirectional scanning,the circuit of the shift register 821 may refer to those shown in FIG.3A, FIG. 5A, and FIG. 7A. That is, the circuit of the shift register 821is similar to the circuit the shift register 621 a but the voltagepull-down unit 230 thereof is replaced with the pull-down unit 530 ofthe shift register 421 a and the pre-charge unit 210 thereof is replacedwith the pre-charge unit 310 of the shift register 121 b.

Additionally, in the embodiments described above, the gate drivingcircuits (such as 120_1, 120_2, 420_1, 420_2, 620_1, 620_2, 820_1, and820_2) are disposed on the both sides of the display area 111. In otherembodiments, however, the gate driving circuits may be integrated into asingle circuit and disposed on a side of the display area 111.Similarly, the pull-down control circuits (such as 130_1, 130_2, 430_1,and 430_2) may also be integrated into a single circuit and disposed ona side of the display area 111. In addition, the push-up controlcircuits (such as 630_1 and 630_2) may also be integrated into a singlecircuit and disposed on a side of the display area 111.

To sum up, in the embodiments of the invention, the display panelremoves the pull-down control units from the shift registers of the gatedriving circuit, so that the removed pull-down control units become anindependent pull-down control circuit. Furthermore, in the embodimentsof the invention, the gate driving circuits and the pull-down controlcircuits of the display panel are disposed in sequence along a side ofthe display area to reduce the circuit area of the gate driving circuitsand to slim down the border of the display panel. Besides, the boostcircuit in the shift registers may be removed, so that the removed bootcircuit may become an independent push-up control circuit, and that thecircuit area of the gate driving circuits may be further reduced.

What is claimed is:
 1. A display panel, comprising: a substrate, havinga display area and a peripheral area; a plurality of pixels, disposed onthe display area; a plurality of scan lines, disposed on the substrateand respectively coupled to the corresponding pixels, the scan linesextending from the display area to the peripheral area; a pull-downcontrol circuit, disposed on the peripheral area, the pull-down controlcircuit receiving a plurality of clock signals and having a plurality ofpull-down units to provide a plurality of first pull-down signals; and agate driving circuit, disposed on the peripheral area and having aplurality of shift registers, wherein the shift registers are coupled tothe scan lines to provide a plurality of gate driving signals, the shiftregisters are coupled to the pull-down control circuit to receive thefirst pull-down signals, the shift registers enable the gate drivingsignals in sequence according to the clock signals, and the shiftregisters pull down the gate driving signals in sequence according tothe first pull-down signals, respectively, wherein the pull-down controlcircuit and the gate driving circuit are arranged along a side of thedisplay area, wherein each of the shift registers comprises: apre-charge unit for pre-charging an internal voltage; a voltage push-upunit, coupled to the pre-charge unit for pushing up i^(th) gate drivingsignal of the gate driving signals according to the internal voltage,wherein i is an positive integer; and a voltage pull-down unit,receiving the corresponding first pull-down signal for pulling down theinternal voltage and the i^(th) gate driving signal according to thecorresponding first pull-down signal, wherein the pull-down unitsfurther provide a plurality of second pull-down signals, and the voltagepull-down unit receives the corresponding second pull-down signal topull down the i^(th) gate driving signal according to the correspondingfirst pull-down signal and to pull down the internal voltage accordingto the corresponding second pull-down signal.
 2. The display panel asclaimed in claim 1, wherein enabling periods of the clock signalspartially overlap and are different from one another.
 3. The displaypanel as claimed in claim 1, wherein the pre-charge unit comprises: afirst transistor, wherein a first terminal of the first transistorreceives a forward scanning voltage, a second terminal of the firsttransistor is coupled to the internal voltage, and a control terminal ofthe first transistor receives (i−1)^(th) gate driving signal of the gatedriving signals or a start signal; and a second transistor, wherein afirst terminal of the second transistor receives a reverse scanningvoltage, a second terminal of the second transistor is coupled to theinternal voltage, and a control terminal of the second transistorreceives (i+1)^(th) gate driving signal of the gate driving signals. 4.The display panel as claimed in claim 1, wherein the voltage push-upunit comprises: a fifth transistor, wherein a first terminal of thefifth transistor receives a first clock signal of the clock signals, asecond terminal of the fifth transistor is coupled to the i^(th) gatedriving signal, and a control terminal of the fifth transistor receivesthe internal voltage; and a first capacitor, coupled between the secondterminal and the control terminal of the fifth transistor.
 5. Thedisplay panel as claimed in claim 4, wherein each of the pull-down unitscomprises: a sixth transistor, wherein a first terminal of the sixthtransistor receives a forward scanning voltage, a second terminal of thesixth transistor is coupled to the corresponding first pull-down signal,and a control terminal of the sixth transistor receives a second clocksignal of the clock signals; and a seventh transistor, wherein a firstterminal of the seventh transistor receives a reverse scanning voltage,a second terminal of the seventh transistor is coupled to thecorresponding first pull-down signal, and a control terminal of theseventh transistor receives a third clock signal of the clock signals.6. The display panel as claimed in claim 5, wherein an enabling periodof the first clock signal and an enabling period of the second clocksignal partially overlap, the enabling period of the first clock signaland an enabling period of the third clock signal partially overlap, aphase of the first clock signal leads a phase of the second clocksignal, and the phase of the first clock signal lags a phase of thethird clock signal.
 7. The display panel as claimed in claim 5, whereinthe forward scanning voltage is one of a gate high voltage and a gatelow voltage, and the reverse scanning voltage is the other one of thegate high voltage and the gate low voltage.
 8. The display panel asclaimed in claim 4, wherein each of the pull-down units comprises: aneighth transistor, wherein a first terminal and a control terminal ofthe eighth transistor receive a fourth clock signal of the clocksignals, and a second terminal of the eighth transistor is coupled tothe corresponding first pull-down signal.
 9. The display panel asclaimed in claim 8, wherein an enabling period of the first clock signaland an enabling period of the fourth clock signal partially overlap, anda phase of the first clock signal leads a phase of the fourth clocksignal.
 10. The display panel as claimed in claim 1, wherein the voltagepull-down unit comprises: a tenth transistor, wherein a first terminalof the tenth transistor receives the corresponding second pull-downsignal, a second terminal of the tenth transistor receives a gate lowvoltage, and a control terminal of the tenth transistor receives theinternal voltage; an eleventh transistor, wherein a first terminal ofthe eleventh transistor is coupled to the internal voltage, a secondterminal of the eleventh transistor receives the gate low voltage, and acontrol terminal of the eleventh transistor receives the correspondingsecond pull-down signal; and a twelfth transistor, wherein a firstterminal of the twelfth transistor is coupled to the i^(th) gate drivingsignal, a second terminal of the twelfth transistor receives the gatelow voltage, and a control terminal of the twelfth transistor receivesthe corresponding first pull-down signal.
 11. The display panel asclaimed in claim 1, wherein each of the pull-down units comprises: athirteenth transistor, wherein a first terminal of the thirteenthtransistor receives a forward scanning voltage, a second terminal of thethirteenth transistor is coupled to the corresponding first pull-downsignal, and a control terminal of the thirteenth transistor receives afifth clock signal of the clock signals; a fourteenth transistor,wherein a first terminal of the fourteenth transistor receives a reversescanning voltage, a second terminal of the fourteenth transistor iscoupled to the corresponding first pull-down signal, and a controlterminal of the fourteenth transistor receives a sixth clock signal ofthe clock signals; a fifteenth transistor, wherein a first terminal ofthe fifteenth transistor receives the forward scanning voltage, a secondterminal of the thirteenth transistor is coupled to the correspondingsecond pull-down signal, and a control terminal of the fifteenthtransistor receives a seventh clock signal of the clock signals; and asixteenth transistor, wherein a first terminal of the sixteenthtransistor receives the reverse scanning voltage, a second terminal ofthe sixteenth transistor is coupled to the corresponding secondpull-down signal, and a control terminal of the sixteenth transistorreceives an eighth clock signal of the clock signals, wherein enablingperiods of the fifth clock signal, the sixth clock signal, the seventhclock signal, and the eighth clock signal overlap with one another, andaccording to phase sequence, these clock signals are arranged in anorder of the sixth clock signal, the seventh clock signal, the fifthclock signal, and the eighth clock signal.
 12. The display panel asclaimed in claim 1, wherein each of the pull-down units comprises: aseventeenth transistor, wherein a first terminal and a control terminalof the seventeenth transistor receive a ninth clock signal of the clocksignals, and a second terminal of the seventeenth transistor is coupledto the corresponding first pull-down signal; and an eighteenthtransistor, wherein a first terminal and a control terminal of theeighteenth transistor receive a tenth clock signal of the clock signals,and a second terminal of the eighteenth transistor is coupled to thecorresponding second pull-down signal, wherein enabling periods of theninth clock signal and the tenth clock signal partially overlap.